Pololu A-Star 32U4 Micro User's Guide
Contents
1. MCUSR 0 2001 2014 Pololu Corporation 7 The A Star 32U4 Bootloader Page 20 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 8 Reviving an unresponsive A Star In order to load a new program onto your A Star you will need to get it into bootloader mode and send programming commands to it over its virtual serial port using appropriate software If you are programming the A Star from the Arduino IDE the sketch loaded onto the A Star will generally support a special USB command for putting the A Star mode in bootloader mode and the Arduino IDE sends that command automatically when you press the Upload button However you might find yourself in a situation where the A Star is unresponsive and that method will not work This can happen for two reasons You accidentally loaded a malfunctioning program onto the A Star that is incapable of responding to the special USB command For example your program might be stuck in an infinite loop with interrupts disabled Youloaded a program which uses a non standard type of USB interface or no USB interface The following sections provide different procedures you can use to revive your A Star 8 1 Reviving using the Arduino IDE This section explains two special methods for programming an A Star using the Arduino IDE in case your usual method of programming is not working These instructions were developed for the Arduino IDE versions 1 0 5 r2 and2. abbreviated A include a 16 MHz resonator a USB Micro B connector an in system programming ISP header and a pair of indicator LEDs A voltage regulator and power selection circuit allow the board to be powered from either USB or an external 5 5 V to 15 V source while a resettable PTC fuse on the USB VBUS supply and reverse protection on VIN help protect it from accidental damage A Star 32U4 Micro bottom view with U S The A Star 32U4 Micro breaks out 15 general purpose I O lines quarter for size reference along two rows of pins including 7 usable as PWM outputs and 8 usable as analog inputs It fits all this into a 20 pin dual in line package DIP measuring only 1 x 0 6 and its 0 1 pin spacing makes the A easy to use with solderless breadboards http www pololu com category 28 solderless breadboards perfboards and 0 1 pitch connectors http www pololu com category 19 connectors Y This product requires a USB A to Micro B cable http www pololu com product 1938 not included to connect to a computer Arduino compatibility The A Star 32U4 ships with a preloaded Arduino compatible bootloader which uses 4 KB of flash memory leaving 28 KB available for the user program We provide a software add on that enables the board to be easily programmed from the Arduino environment The A Star 32U4 uses the same microcontroller as the Arduino Leonardo http www pololu com product 2192 and Arduino Micro http w
3. Print queues n ES Drnrecenre Windows 8 device manager showing the A Star s virtual COM port 6 Open up the Blink Arduino example which can be found under File gt Examples gt 01 Basics gt Blink The code in this example will make the A Star blink its yellow LED When you select the Blink example a new Arduino IDE window will open up It is OK to close the first window 5 Getting Started Page 11 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation oo Edit Sketch Tools Help New Open Sketchbook AnalogReadSerial Close Ctrl W 02 Digital BareMinimum Save Ctrl S 03 Analog Save As Ctrl Shift S 04 Communication gt DigitalReadSerial Upload Ctrl U 05 Control Fade Upload Using Programmer Ctrl Shift U 06 Sensors ReadAnalogVoltage Page Setup Ctrl Shift P acted d d 08 Strings Selecting the Blink example in the Arduino IDE 7 Press the Upload button to compile the sketch and upload it to the A Star If everything goes correctly you will see the message Done uploading appear near the bottom of the window If you are using Windows and you have not previously programmed an A Star on this USB port then Windows might take several seconds to recognize the A Star bootloader The bootloader times out after 8 seconds and goes back to running the sketch so the upload might fail 1f Windows does not recognize it quickly enough If this ha
4. a wiki called the The Arduino Playground http playground arduino cc and other resources The A Star is very similar to the Arduino Leonardo http www pololu com product 2192 and Arduino Micro http www pololu com product 2188 so you can search the Internet for relevant projects that use one of those boards Atmel s ATmega32U4 documentation http www atmel com devices atmega32u4 aspx has the ATmega32U4 datasheet and many related documents AVR Libc Home Page http www nongnu org avr libe this page documents the standard library of functions that you can use with GNU C and C compilers for the AVR LUFA the Lightweight USB Framework for AVRS http www fourwalledcubicle com LUFA php WinAVR http winavr sourceforge net Atmel Studio 6 http www atmel com microsite atmel_studio6 AVRDUDE http www nongnu org avrdude AVR Freaks http www avrfreaks net Finally we would like to hear your comments and questions on the A Star section of the Pololu Robotics Forum http forum pololu com viewforum php f 10 9 Related Resources Page 24 of 24
5. in Devices by connection mode showing that the A Star is a composite device On a Linux computer you can see details about the A Star s USB interface by running lsusb v d iffb ina Terminal The virtual serial port can be found by running 1s dev ttyacm in a Terminal On a Mac OS X computer the virtual serial port can be found by running 1s dev tty usbmodem in a Terminal You can send and receive bytes from the A Star s virtual serial port using any terminal program that supports serial ports Some examples are the Serial Monitor in Arduino IDE the Pololu Serial Transmitter Utility http www pololu com docs 0J23 Br y Terminal http sites google com site terminalbpp PuTTY http www chiark greenend org uk sgtatham putty TeraTerm http ttssh2 sourceforge jp Kermit http www columbia edu kermit ck80 html and GNU Screen http www gnu org software sereen Many computer programming environments also support sending and receiving bytes from a serial port 6 The A Star 32U4 USB Interface Page 17 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 7 The A Star 32U4 Bootloader The A Star comes with a USB bootloader that can be used in conjunction with the Arduino IDE or AVRDUDE to load new programs onto the A Star This section documents some technical details of the bootloader for advanced users who want to better understand how it works If you just want to get started using your A Star
6. it is fine to skip this section The A Star 32U4 Bootloader is based on the Caterina bootloader https github com arduino Arduino tree master hardware arduino bootloaders caterina which is the bootloader used on the Arduino Leonardo http www pololu com product 2192 Arduino Micro http www pololu com product 2188 and several other ATmega32U4 boards The bootloader is open source and its source code https github com pololu a star tree master bootloaders caterina is available on GitHub The bootloader occupies the upper four kilobytes of the ATmega32U4 s program memory leaving 28 KB for the user program The bootloader s USB interface consists of a single virtual serial port that accepts the programming commands defined in AVR109 http www atmel com images doc1644 pdf The bootloader always runs first immediately after the AVR is reset Startup logic The main difference between the A Star 32U4 Bootloader and Caterina is in the startup logic This is the part of the bootloader that runs immediately after the AVR is reset and it decides whether to run the user program or run the rest of the bootloader The startup logic of the Caterina bootloader is designed so that when the RST line goes low the bootloader will run This means that if you want to restart your program using the RST line it will take 8 seconds before the bootloader times out waiting for an upload and the sketch starts The A Star 32U4 has different startup logic
7. send programming commands The bootloader before uploading method The goal of the bootloader before uploading method is to select the bootloader s virtual serial port in the Arduino IDE and then make sure the board is in bootloader mode at the time when the Arduino IDE enters the uploading phase 1 Connect the A Star to your computer via USB 2 In the Tools menu open the Board sub menu and check to see if the Pololu A Star 32U4 bootloader port entry is visible If this entry is visible you can skip to step 6 3 If you are using a 1 0 x version of the Arduino IDE open the file sketchbook location hardware pololu boards txt using a text editor If you are using a 1 5 x version of the Arduino IDE open the file sketchbook location hardware pololu avr boards txt using a text editor You can see the sketchbook location in the Arduino IDE preferences dialog The file you are looking for is part of the A Star add on 4 In the boards txt file that you opened find the lines at the bottom of the file that start with ta star32U4bp Uncomment each of those lines by deleting the character and then save the file 5 Close the Arduino IDE and restart it 6 In the Tools menu open the Board sub menu and select Pololu A Star 32U4 bootloader port This entry is configured so that the Arduino IDE will send programming commands directly to selected serial port instead of trying to send a special USB comm
8. should see the yellow LED fading in and out when the AVR is in bootloader mode While it is in bootloader mode quickly look at the list of serial ports provided by your operating system in order to determine what port the bootloader is assigned to 4 Type the following command in your terminal and replace COMA with the name of the bootloader s serial port but do not press enter yet This command will erase the malfunctioning program on the A Star but preserve the bootloader avrdude c avr109 p atmega32U4 P COM4 e 5 Press the reset button twice within 750 ms to make the AVR go into bootloader mode 6 Quickly run the command you typed previously The command needs to be run within 8 seconds of starting the bootloader or else the bootloader will exit and try to run the malfunctioning program again By following the instructions above the malfunctioning program on the A Star will be erased and the A Star will stay in bootloader mode indefinitely You can now load another program onto it using the Arduino IDE or AVRDUDE 8 Reviving an unresponsive A Star Page 23 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 9 Related Resources To learn more about using the Pololu A Star see the following list of resources The Arduino IDE has many examples http arduino cc en Tutorial HomePage that can run on the A Star The Arduino website has a Language Reference http arduino cc en Reference HomePage
9. sketchbook location will be a folder named Arduino inside the Arduino IDE Documents folder For a typical Windows user running a recent version of Windows the pololu folder should be installed in this location C WUsersvcusername Documents Arduino hardwarelpololu If the Arduino or hardware directories do not exist yet you will need to create them 3 Close the Arduino IDE if it is open and then restart it 5 Getting Started Page 10 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 4 In the Tools gt Board menu select the Pololu A Star 32U4 entry If you do not see the A Star listed in the Board menu then the add on is probably not installed correctly Try doing step 2 again and restarting the Arduino IDE Arduino NG or older w ATmegal68 Arduino NG or older w ATmega Arduino Robot Control Arduino Robot Motor Pololu A Star 32U4 Selecting the Pololu A Star 32U4 in the Boards menu 5 In the Tools gt Port menu select the port for the A Star On Windows you can determine what COM port the A Star is assigned to by looking at the Ports COM amp LPT section of the Device Manager On Linux the port name will begin with dev tty ACM On Mac OS X the port name will begin with dev tty usbmodem File Action View Help e9 m U mt gt Other devices b KK Portable Devices a Y Ports COM amp LPT Y Pololu A Star 32U4 COM7 gt dh
10. this way your computer will then recognize it as a Leonardo for example its entry in the Windows Device Manager will display Arduino Leonardo After you succeed in programming the A Star from the Arduino IDE there are many resources you can use to learn more The Arduino IDE has many examples http arduino cc en Tutorial HomePage that can run on the A Star The Arduino website has a Language Reference http arduino cc en Reference HomePage a wiki called the The Arduino Playground http playground arduino cc and other resources e The A Star is very similar to the Arduino Leonardo http www pololu com product 2192 and Arduino Micro http www pololu com product 2188 so you can search the Internet for relevant projects that use one of those boards Section 9 lists many more resources 5 3 Programming using avr gcc and AVRDUDE This sections explains how to program the A Star using the avr gcc toolchain and AVRDUDE This section is intended for advanced users who do not want to use the Arduino IDE as described in Section 5 2 5 Getting Started Page 13 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation Getting the prerequisites If you are using Windows we recommend downloading WinAVR http winavr sourceforge net which contains the avr gcc toolchain and a command line utility called AVRDUDE http www nongnu org avrdude that can be used to upload programs to the A Star b
11. 1 5 6 12 and they might need to be modified for future versions Reset button If you have not done so already you should connect a momentary pushbutton http www pololu com product 1400 between the GND and RST pins of the A Star to serve as a reset button Alternatively you can use a wire to temporarily connect GND and RST together instead of using a reset button Resetting the board twice within 750 ms makes the board go into bootloader mode The bootloader will exit after 8 seconds and try to run the sketch again if it has not started receiving programming commands To revive the A Star you need to make sure you start sending it programming commands before the 8 second period is over In bootloader mode the yellow LED the one labeled L fades in and out It is useful to look at this LED so you can know what mode the microcontroller is in Also we recommend enabling verbose output during upload using the Arduino IDE s Preferences dialog Looking at the LED and looking at the verbose output during the following procedures will help you understand what is going on The uploading before bootloader method Arduino 1 0 x only The goal of the uploading before bootloader method is to select a non existent serial port in the Arduino IDE and then make sure the Arduino IDE enters the uploading phase before the microcontroller goes into bootloader mode This method does not work on the Arduino IDE 1 5 6 r2 and later because those versions of
12. New Hardware Wizard select Install the software automatically and click Next 8 Windows XP will warn you again that the driver has not been tested by Microsoft and recommend that you stop the installation Click Continue Anyway 9 When you have finished the Found New Hardware Wizard click Finish 5 2 Programming using the Arduino IDE The Pololu A Star can be programmed from the popular Arduino integrated development environment IDE The Arduino IDE is a cross platform open source application that integrates a C code editor the GNU C compiler and a program upload utility To get started programming the A Star with the Arduino IDE follow these steps 1 Download the Arduino IDE from the Arduino Download page http arduino cc en Main Software and install it You can download either the 1 0 x version or the 1 5 x version the A Star supports both 2 If you have not done so already download the A Star Software and Drivers http www pololu com file download a star 1 0 1 zip file id 0J743 98k zip These files are also available from the A Star repository on GitHub https github com pololu a star Copy the pololu folder from the downloaded add on folder into the sketchbook location hardware folder You can see the sketchbook location in the Arduino IDE Preferences dialog which is available from the File menu For a typical user Programming the A Star 32U4 from the the
13. Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation Pololu A Star 32U4 Micro User s Guide 1 2 3 4 5 9 Overview 2 1 1 Supported Operating Systems si eoe EU ee E Y x N EOEOE eee Yos a 4 Contacting Pololu zb ko R9 be RUE RU SR RC ue OS NOE SOS See E e ORO UR E Rd 5 Pinout and Components s sss soos 425 08 a ob OR Do 3o VOR p 4 4 X FOX S 3o 9 2 De wg 6 Schematic Diagram 2 S os s s s 8 Getting Started y vou OE Yon Ease ede X oU Re a a eee ee RR eee 9 5 1 Installing Windows Drivers ross 9 52 Programming using the Arduino IDE ee 10 5 3 Programming using avr gcc and AVRDUDE 2 e 13 The A Star 3204 USB Interfaces zio pude s ox Nobb ee ee 4 aa dU BS d E EQ 16 The A Star 32U4 Bootloader ao ec s o ke be RUE RE UE EN UE ON DR E Xue OY Rp ee eS 18 Reviving an unresponsive A Star 222 lll s 21 8 1 Reviving using the Arduino IDE 2222s 21 82 Reviving using AVRDUDE ote x o4 Ee Y 4e VOX RDAS WU Y Nox EOXDESAD OX RON 23 Related Resources iia ew c AR eee A E ER REESE GEES SETS ES 24 http www pololu com docs 0J61 all Page 1 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 1 Overview The Pololu A Star 32U4 Micro is a general purpose programmable module based on Atmel s ATmega32U4 AVR microcontroller which has 32 KB of flash program memory 2 5 KB of RAM and built in USB functionality Onboard features of the A Star
14. Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 6 The A Star 32U4 USB Interface The A Star 32U4 Micro is based on a single AVR ATmega32U4 microcontroller that runs the user program and also handles the USB connection to the computer The AVR has a full speed USB transceiver built into it and can be programmed to present almost any type of USB device interface to the computer USB is an asymmetric system that consists of a single host connected to multiple devices The host is typically a personal computer The ATmega32UA can only act as a USB device so the A Star cannot be connected to other USB devices it can only be connected to a host such as your computer Programming the A Star using the Arduino IDE as described in Section 5 2 will automatically configure it as a composite device with a single virtual serial port and a human interface device HID with a keyboard and mouse Since we preload an example Arduino sketch on each A Star before it ships this is the default USB configuration of the A Star On a Windows computer you can see the virtual serial port by going to your computer s Device Manager and expanding the Ports COM amp LPT list You should see a COM port labeled Pololu A Star 32U4 In parentheses after the name you will see the name of the port e g COM3 or COM4 Windows will assign a different COM port number to the A Star depending on what USB port you plug it into and whether
15. and to the port to get it into bootloader mode and then waiting for the new port to appear By selecting this entry the timing of the programming process below becomes easier especially on Windows 7 Prepare the computer to show you a list of its virtual serial ports If you are using Windows this means you should open the Device Manager If you are on Linux or Mac OS X this means you should open a Terminal and type the command 1s dev tty but do not press enter until the board is in bootloader mode in the next step 8 Reset the board twice to get the board into bootloader mode While it is in bootloader mode quickly look at the list of serial ports provided by your operating system in order to determine what port the bootloader is assigned to 9 Reset the board twice to get the board into bootloader mode again While the board is in bootloader mode quickly select the serial port of the bootloader in the Arduino IDE The port can be selected in the Port sub menu under Tools 10 In the Arduino IDE click the Verify button to compile your sketch This could make the timing easier during the next step 11 Press the reset button twice to get the board into bootloader mode again As soon as you see the yellow LED fading in and out press the Upload button The Arduino IDE will compile your sketch and then upload it to the selected serial port If the compilation of the sketch takes longer than 8 seconds then this proce
16. ct 1300 1 1 Supported Operating Systems The A Star can be programmed using any operating system that supports the Arduino environment We have tested the A Star our Arduino software add on and the Arduino IDE on Microsoft Windows 8 1 8 7 Vista XP with Service Pack 3 Linux and Mac OS X 1 Overview Page 4 of 24 Pololu A Star 32U4 Micro User s Guide 2 Contacting Pololu We would be delighted to hear from you about any of your projects and about your experience with the Pololu A Star You can contact us http www pololu com contact directly or post on our forum http forum pololu com Tell us what we did well what we could improve what you would like to see in the future or anything else you would like to say O 2001 2014 Pololu Corporation 2 Contacting Pololu Page 5 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 3 Pinout and Components Pinout x J 3 3 V output O N OC hh O O J 00 qo KIOS J VIN 5 5 15 V ISP pins The diagram above identifies the I O and power pins on the A Star 32U4 Micro yellow labels represent digital I O pins and green labels represent analog input channels Light text on a dark background indicates Arduino digital and analog pin numbering which can be used to refer to the pins when writing code in the Arduino environment Dark text on a light background indicates a name or function of the pin as defined in the ATmega32UA datashe
17. dure will fail because the bootloader will time out and start trying to run the malfunctioning sketch again If that happens try the procedure again using a simpler sketch such as the Blink example that can be found under File gt Examples gt 01 Basics gt Blink 8 Reviving an unresponsive A Star Page 22 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 82 Reviving using AVRDUDE This section explains a special method for reviving an A Star using the command line utility AVRDUDE http www nongnu org avrdude in case your usual method of programming is not working AVRDUDE stands for AVR Downloader UploaDEr and it is compatible with the A Star bootloader If you have not done so already you should connect a momentary pushbutton http www pololu com product 1400 between the GND and RST pins of the A Star to serve as a reset button Alternatively you can use a wire to temporarily connect GND and RST together instead of using a reset button 1 Connect the A Star to your computer via USB 2 Prepare the computer to show you a list of its virtual serial ports If you are using Windows this means you should open the Device Manager If you are on Linux or Mac OS X this means you should open a Terminal and type the command 1s dev tty but do not press enter until the board is in bootloader mode in the next step 3 Press the reset button twice within 750 ms to make the AVR go into bootloader mode You
18. ections Wl relax CC avr gcc TARGET main OBJECT FILES main o all S TARGET hex clean rt f o hex obj hex hex 0bj avr objcopy R eeprom O ihex lt Se 5 Getting Started Page 14 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 0bj S OBJECT FILES CC CFLAGS S OBJECT FILES LDFLAGS o program TARGET hex avrdude p MCU c avr109 P S PORT U flash w TARGET hex Make sure that the PORT variable in the Makefile is set to the name of the A Star s virtual serial port In Windows USBSERO00 should work if the A Star is the only USB device connected that is using the usbser sys driver but you can change it to be the actual name of the COM port e g com13 In a command prompt navigate to the directory with the Makefile and main c If you run the command make the code should get compiled and produce a file named main hex Programming To program the A Star you will need to get it into bootloader mode first One way to do this is to reset the AVR twice within 750 ms A pushbutton can be connected between the GND and RST pins to serve as a reset button or you can use a wire Once the A Star is in bootloader mode quickly run the command make progran to program the A Star If you wait longer than 8 seconds the A Star bootloader will exit and the AVR will go back to running the user program 5 Getting Started Page 15 of 24 Pololu A
19. et For more information about the ATmega32U4 microcontroller on this board see Atmel s ATmega32U4 documentation http www atmel com devices atmega32u4 aspx Printed on the A Star are indicators that you can use to quickly identify each pin s capabilities a triangle next to the pin means it can be used as an analog input and a square wave symbol under the pin number means it can be used as a PWM output LEDs The A Star 32U4 Micro has two indicator LEDs The yellow LED is connected to Arduino pin 13 or PC7 You can drive this pin high in a user program to turn this LED on The A Star 32U4 Bootloader http www pololu com docs 0J61 7 fades this LED on and off while it is waiting for a sketch to be loaded The green LED is connected to PD5 and lights when the pin is driven low While the board is running the A Star 32U4 Bootloader or a program compiled in the Arduino environment it will flash this LED when it is transmitting data via the USB connection Connectors The A Star 32U4 includes a USB Micro B connector that can be used to connect to a computer s USB port via a USB A to Micro B cable http www pololu com product 1938 not included The USB connection can be used to transmit 3 Pinout and Components Page 6 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation and receive data from the computer and a preloaded USB bootloader makes it possible to program the board over USB The USB connection ca
20. it is in bootloader mode or not If you need to change the COM port number assigned to the A Star you can do so using the Device Manager Double click on the COM port to open its properties dialog and click the Advanced button in the Port Settings tab From this dialog you can change the COM port assigned to the A Star File Action View Help gm ss gt gt Other devices gt Portable Devices a Y Ports COM amp LPT Pololu A Star 32U4 COM7 gt dh Print queues OF Drnrecenre Windows 8 device manager showing the A Star s virtual COM port On a Windows computer you can see the rest of the A Star s USB interface by going to the Device Manager selecting View gt Devices by connection and then expanding entries until you find the Pololu A Star 32U4 COM port Near it you should see the parent composite device and the human interface device 6 The A Star 32U4 USB Interface Page 16 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation File Action View Help es OB tig mI 4 9 Intel R USB 3 0 eXtensible Host Controller 0100 Microsoft a USB Root Hub xHCI b o Dell Wireless 1703 Bluetooth b v USB Composite Device 4 0 USB Composite Device Y Pololu A Star 32U4 COM7 4 5 USB Input Device lt HID Keyboard Device P HID compliant mouse b 05 USB Input Device gt USB Mass Storage Device i PCI standard host CPU bridae The Windows 8 Device Manager
21. n also provide power to the A Star The board also has a 6 pin ISP header that allows it to be programmed with an external programmer such as our USB AVR programmer http www pololu com product 1300 Pin 1 of the header is indicated with a small white dot and has an octagonal shape Power The A Star 32U4 Micro can either be powered directly from the USB 5 V supply or from a separate source on the VIN pin The board features a power selection circuit that allows both USB and VIN to be connected at the same time if this is done the A Star will draw power from USB USB power input The A Star can be powered from the USB 5 V bus voltage VBUS if it is connected to a USB cable A resettable PTC fuse on VBUS makes it less likely for the A Star and the connected computer or other device to be damaged if too much current is drawn from the USB connection VIN power input The A Star can be powered from VIN if you connect a 5 5 V to 15 V power supply such as a battery or wall power adapter to the VIN and GND pins with the positive terminal connected to VIN It will draw power from VIN only if USB is disconnected When powering the A Star 32U4 Micro from VIN a minimum voltage of 5 5 V is required to ensure that the board s 5 V supply is stable Even if power is being provided to the A Star via USB connecting a voltage higher than 0 V but lower than 5 5 V to VIN is not recommended as this can interfere with the power selection circuit and cau
22. ootloader If the version of GNU make that comes with WinAVR crashes on your computer we recommend using the Pololu version of GNU make https github com pololu make releases If you are using Mac OS X we recommend downloading the CrossPack for AVR Development http www obdev at products crosspack If you are using Linux you will need to install avr gcc avr libe and AVRDUDE Ubuntu users can get the required software by running sudo apt get install gcc avr avr libc avrdude After you have installed the prerequisites open a command prompt and try running these commands to make sure all the required utilities are available avr gcc v avr objcopy V make v avrdude If any of those commands fail make sure the desired executable is installed on your computer and make sure that it is in a directory listed in your PATH environment variable Compiling an example program Copy the following code to a file named main c tdefine F CPU 16000000 include lt avr io h gt include lt util delay h gt int main DDRC 1 lt lt DDC7 Make pin 13 be an output while 1 PORTC 1 lt lt PORTC7 Turn the LED on delay ms 500 PORTC 1 lt lt PORTC7 Turn the LED off delay ms 500 In the same folder create a file named Makefile with the following contents PORT USBSERO00 MCU atmega32u4 CFLAGS g Wall mcall prologues mmcu MCU Os LDFLAGS W1 gc s
23. ot tell you when the installation is complete but it should be done after a few seconds 5 Getting Started Page 9 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation Windows 8 Windows 7 and Windows Vista users After installing the drivers your computer should automatically recognize the A Star when you connect it via USB No further action from you is required However the first time you connect an A Star to your computer Windows will take several seconds to recognize the device and configure itself properly The first time you program the A Star Windows will again take several seconds to recognize the A Star s USB bootloader and this could cause the programming operation to fail the first time Also Windows will need to re recognize the A Star and the bootloader if you connect the board to another USB port that it has not been connected to before Windows XP users After installing the drivers you will need to follow steps 5 9 for each new A Star you connect to your computer You will also need to follow these steps the first time you attempt to program the A Star in order to make Windows recognize the bootloader and when you connect the A Star to a different USB port that it has not been connected to before 5 Connect the A Star to your computer s USB port 6 When the Found New Hardware Wizard is displayed select No not this time and click Next 7 On the second screen of the Found
24. ppens try again If you are using Windows XP and have not programmed an A Star on this USB port you will have to go through the Found New Hardware Wizard again as described in Section 5 1 but the second time you try to upload it should work If the Arduino IDE has trouble connecting to the port or using it try unplugging the A Star closing any programs that might be using the serial port restarting the Arduino IDE and then plugging the A Star back in 5 Getting Started Page 12 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation eo File igita Sketch Tools Help o Upload void setup initialize the digital pin as an output pinMode led OUTPUT the loop routine runs over and over again forever 434 Tones f Pololu A Star Uploading a sketch to the A Star using the Arduino IDE 8 Ifyou uploaded the Blink sketch then the A Star s yellow LED should be blinking once every two seconds However we ship the A Star with that same example already programmed onto it so you might not be convinced that anything has changed Try changing the delay values in the sketch to something else and uploading again to see if you can change the speed of the LED The A Star is similar enough to the Arduino Leonardo that you do not actually have to install the add on If you want to you can just select the Arduino Leonardo board in the Arduino IDE Note that if you upload a sketch to the A Star
25. se the 5 V line to drop potentially triggering a brown out reset 5V power output This pin provides access to the board s 5 V supply which comes from either the USB 5 V bus voltage or a low dropout LDO regulator on VIN depending on which power source is connected The regulator can supply up to 100 mA although some of this is used by the board itself typically about 25 mA or used to provide current for the GPIO pins or 3 3 V power output see below 3V3 power output This pin gives access to the output of the internal 3 3 V regulator inside the ATmega32U4 The microcontroller uses this regulated voltage for USB signaling but up to about 50 mA is available for powering external circuits or devices When the A Star 32U4 Micro is being powered through VIN the sum of the 5V output current 3V3 output current GPIO output current and current used by the board itself should not exceed the 100 mA that the regulator can provide 3 Pinout and Components Page 7 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 4 Schematic Diagram THES Pololu A Star 32U4 Micro schematic diagram This schematic is also available as a printable PDF http www pololu com file download pololu a star 32U4 micro schematic diagram pdf file_id 0J742 253k pdf 4 Schematic Diagram Page 8 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 5 Getting Started 5 1 Installing Windows Dri
26. that allows you to use the RST line to reset the board with a smaller delay If the RST line goes low once the user program will run after a 750 ms delay If the RST line goes low twice within 750 ms then the bootloader will run This behavior is the same as on boards like SparkFun s Pro Micro The start up logic of the A Star 32U4 bootloader is shown in the flowchart below 7 The A Star 32U4 Bootloader Page 18 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation Sketch uploaded or sketch was already present and 8 seconds elapsed The startup logic for the A Star 32U4 bootloader Brown out detection Unlike many other ATmega32UA boards the A Star has brown out detection enabled The A Star s brown out threshold is 4 3 V and if the voltage on VCC goes below this then the AVR will reset The A Star bootloader was designed so that the user program can detect brown out resets To do so check to see if the BORF bit in the MCUSR register is set and then clear it later Here is some example code you could put in your setup function for detecting brown out resets 7 The A Star 32U4 Bootloader Page 19 of 24 Pololu A Star 32U4 Micro User s Guide pinMode 13 OUTPUT AE MCUSR amp 1 lt lt BORF A brownout reset occurred Blink the LED quickly for 2 seconds for uint8 t i 0 i 10 i digitalWrite 13 HIGH delay 100 digitalWrite 13 LOW delay 100
27. the IDE give a fatal error message if the selected serial port is not present at the beginning of the uploading phase e g Board at COM7 is not available 1 Connect the A Star to your computer via USB 2 In the Tools menu open the Board sub menu and select Pololu A Star 32U4 3 In the Tools menu open the Port sub menu and check to see if any ports are selected If the Port menu is grayed out or no ports in it are selected that is good and you can skip to step 6 4 Resetthe board twice to get the board into bootloader mode While the board is in bootloader mode quickly select the new serial port that corresponds to the bootloader in the Port menu 5 After 8 seconds the bootloader will exit and attempt to run the sketch again Wait for the bootloader to exit Verify that either the Port menu is grayed out or no ports in it are selected 8 Reviving an unresponsive A Star Page 21 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation 6 Click the Upload button The Arduino IDE will compile your sketch and start uploading it 7 As soon as the large status bar near the bottom of the IDE says Uploading press reset the board twice to get into bootloader mode The Arduino IDE will stay in the uploading phase for 10 seconds waiting for a new serial port to appear Once the serial port of the bootloader appears the Arduino IDE will connect to it and
28. vers Y If you use Windows XP you will need to have either Service Pack 3 http www microsoft com downloads details aspx FamilyId 68C48DAD BC34 40BE 8D85 6BB4F56F5110 or Hotfix KB918365 installed before installing the drivers for the A Star Some users who installed the hotfix have reported problems which were solved by upgrading to Service Pack 3 so we recommend Service Pack 3 over the hotfix Before you connect your Pololu A Star 32U4 Micro to a computer running Microsoft Windows you must install its drivers 1 Download the A Star Software and Drivers http www pololu com file download a star 1 0 1 zip file_id 03743 98k zip and extract the ZIP file to a temporary folder on your computer These files are also available from the A Star repository on GitHub https github com pololu a star 2 Open the drivers folder Right click on a star inf and select Install 2 pololu ca Open Install Print Open with Send to gt 3 Windows will ask you whether you want to install the drivers Click Install Windows 8 7 and Vista or Contiue Anyway Windows XP Would you like to install this device software Name Pololu A Star Drivers a Publisher Pololu Corporation C Always trust software from Pololu Corporation Don t Install Y You should only install driver software from publishers you trust How can decide which device software is safe to install 4 Windows will n
29. ww pololu com product 2188 and runs at the same frequency making it just as powerful Although the larger boards offer a few more I O pins the A Star 32U4 Micro fits in an area half that of the Arduino Micro and it takes up only 11 as much area as a standard full size Arduino 1 Overview Page 2 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation e ARDUINO ey pa EL gt POWER AN o lt Pololu A Star 32U4 Micro Arduino Micro and Arduino Leonardo 1 Overview Page 3 of 24 Pololu A Star 32U4 Micro User s Guide O 2001 2014 Pololu Corporation Features Dimensions 1 x 0 6 1 05 x 0 6 including USB Micro B connector Programmable 16 MHz Atmel ATmega32U4 AVR microcontroller o 32 KB flash 4 KB used by bootloader leaving 28 KB available for user program by default o 2 5 KB SRAM o 1 KB EEPROM o Native full speed USB 12 Mbps e Preloaded with Arduino compatible bootloader Many I O lines in a small package o 15 general purpose I O pins available along the sides of the board o 3 additional I O pins available on ISP header o 7pins can be configured as hardware PWM outputs o 8 pins can be configured as analog inputs e 2 user controllable LEDs Can be powered from USB or external 5 5 V to 15 V source on VIN PTC fuse on VBUS supply Reverse voltage protection on VIN supply 6 pin ISP header for use with an external programmer http www pololu com produ
Download Pdf Manuals
Related Search